Accession Number:

ADA025692

Title:

A Mathematical Model for the Starting Process of a Transonic Ludwieg Tube Wind Tunnel

Descriptive Note:

Final rept. Jul 1974-Apr 1975

Corporate Author:

ARNOLD ENGINEERING DEVELOPMENT CENTER ARNOLD AFB TN

Personal Author(s):

Report Date:

1976-06-01

Pagination or Media Count:

138.0

Abstract:

A simplified mathematical model is presented for the unsteady flow process of starting a transonic Ludwieg tube wind tunnel. The hardware modeled consists of a porous-walled test section surrounded by a plenum chamber with an exhaust system independent of the tunnels main starting valves, which are located downstream of the diffuser-test section. In the present method, the hardware is modeled as three control volumes the plenum, the test section, and the diffuser. The plenum is treated with the unsteady integral continuity equation with one-dimensional influx or outflux through the porous wall, through the plenum exhaust system, and through the flaps, which exhaust into the diffuser. The other two control volumes are treated with the steady integral continuity equation and a steady, adiabatic, one-dimensional energy equation whose stagnation conditions vary in time according to the classical solution for an unsteady expansion wave. Numerical solutions are compared with experimental pressure-time histories of a small, transonic, high Reynolds number tunnel referred to as HIRT. Agreement between the model and experiment is good.

Subject Categories:

  • Numerical Mathematics
  • Test Facilities, Equipment and Methods
  • Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE